1. Field of the Invention
This invention relates to annunciators, and more particularly to mechanically operated indicator apparatus.
2. Description of the Prior Art
Safety requirements dictate that the occurrences of certain events cannot be signalled electrically, electro-mechanically, or electronically. Thus, for an indication of when a tank is filled with a volatile fuel under pressure, and fueling operations should cease, it is essential that a visible signal be effected mechanically. Further, it is highly desirable that such a mechanical annunciator be extremely sensitive and provide a reliable indication instantaneously with the pressure reaching a predetermined level.